exchange server mail in queue, sender is spoofed

I have mail in my outbound queues (exchange server 2003) that shows the sender as "job@careerbuilder.com". I need to ascertain which workstation on the network is actually sender these emails (100's of them). Virus scans come up clean. I suspected a couple workstations as the culprit, but there is nothing I can find on their PC's to validate this. Sent folders are normal. No virus reported.

How can I looked at one of these stuck in the outgoing queues and determine which workstation (all with static ip's if that helps) sent the message?

Have a read of my article and see if you are an Authenticated Relay:
http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_2556-Why-are-my-outbound-queues-filling-up-with-mail-I-didn't-send.html

I read through the articles. I had already accomplished some of the recommendations as this happened a few days ago initially. Comcast blacklisted the domain although all blacklist tests were clean. Just reran tests through mxtoolbox an the domain appears clean, reverse dns, not an open relay etc all come up clean.

I did uncheck the basic and windows authentication as described in the 2nd article.

How can I tell (or can I tell) which workstation is sending the emails?

Do you feel like you are taking up all of your time constantly visiting users’ desks to make changes to email signatures? Wish you could manage all signatures from one central location, easily design them and deploy them quickly to users? Well, there is an easy way!

Well - if the source is internal, then you can use something like Wireshark to sniff the network for activity to the server using port 25.

If it isn't a client, then if you have killed basic and integrated windows auth on the SMTP Virtual Server and then restarted it, once the queue has been emptied of crap (you can use aqadmcli.exe to speed that up), then the queue should remain empty of crap, although it may take a while to empty the queue as a spammer would send thousands of spam messages and your server can't add them to the queue at the same time, so they queue up and then enter the queue once the server can actually process them, which can take a while, so once emptied, the queue may fill again, you then empty it and repeat until the queue is gone.

Here's is something I have noticed. Quite a few of the queues (which I have currently frozen) are bogus. Mispelled or out of the country email domains such as hotmaim.com, comcaster.net or asia.yahoo.com, gmail.com.co. Almost as though a list of bad email addresses has been accessed. It may just be these queues are in a retry state because the domain isn't valid and the valid ones have already connected and sent the emails.

I have done all that you suggested, hopefully this works. I will continue to monitor this after I finish clearing the queues.

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